The antialgal activity of 40 medicinal plants against Microcystis aeruginosa

Abstract

In search of a botanical algicide, 40 traditional medicinal plants were screened for antialgal activity against the bloom-forming cyanobacterium Microcystis aeruginosa using coexistence culture system assay. The results of the coexistence assay showed that significant inhibition of the algae at 800 mg L −1 were observed for methanolic extracts of the root of Salvia miltiorrhiza (Radix Salviae Miltiorrhizae), rhizome of Acorus tatarinowii (Rhizoma Acori), rhizome of Polygonum cuspidatum (Rhizoma Polygoni), cortex of Phellodendron amurense (Cortex Phellodendri), and fruits of Crataegus pinnatifida (Fructus Crataegi). Methanol extract of these plants were further partitioned with petroleum ether, chloroform, ethyl acetate, and acetone to obtain allelopathically active fractions with various polarity. Among these fractions tested, the ethyl acetate extract of S. miltiorrhiza was observed to be more efficient than the other plant extracts with the inhibitory rate (IR) of 91.3% at 800 mg L −1 and 50% effective concentrations (EC 50 ) values 98.9 mg L −1 after 7 days, followed by chloroform extracts of A. tatarinowii, S. miltiorrhiza, and P. cuspidatum, and the petroleum ether extracts of A.tatarinowii with EC 50 102.5, 111.5, 122.9, and 130.0 mg L −1 , respectively.

Effect of Selected Plant Extracts and D- and L-Lysine on the Cyanobacterium Microcystis aeruginosa

“…The effect of S. miltiorrhiza root extract in our study was less than reported in the literature, where extract of 800 mg L −1 caused an inhibition of 95% [20]. This difference could be due to different extracting procedures: methanolic extracts that were reconstituted in DSMO [20], whereas in our study a water extract was used.…”

“…This difference could be due to different extracting procedures: methanolic extracts that were reconstituted in DSMO [20], whereas in our study a water extract was used. The EC 50 of the water extract in our study was above 640 mg L for methanol extracts [20].…”

“…This difference could be due to different extracting procedures: methanolic extracts that were reconstituted in DSMO [20], whereas in our study a water extract was used. The EC 50 of the water extract in our study was above 640 mg L for methanol extracts [20]. An active compound in the ethyl-acetate extract has been identified as neo-przewaquinone A with a corresponding EC 50 value of 4.7 mg L −1 [37].…”

“…An active compound in the ethyl-acetate extract has been identified as neo-przewaquinone A with a corresponding EC 50 value of 4.7 mg L −1 [37]. It has been proposed that active ingredients with anti-algal activity should be extracted for formulation of a natural algicide [20]. Although the example of S. miltiorrhiza root extract shows purification can lower the EC 50 value and thus application dose, this procedure results in a much higher price [16] and limited availability [18].…”

“…The majority of these products are compounds extracted from plant tissues and tested on M. aeruginosa [17][18][19]. In such testing, extracts from Fructus mume [19], Salvia miltiorrhiza (Chinese Danshen) [20] and extracts from seeds of the pan tropical tree Moringa oleifera [21] are observed to express anti-cyanobacterial activity against M. aeruginosa. In addition, the amino acid L-lysine is reported as active against cyanobacteria [22][23][24].…”